code: def test_defined(value: t.Any) -> bool:
      """Return true if the variable is defined:
  
      .. sourcecode:: jinja
  
          {% if variable is defined %}
              value of variable: {{ variable }}
          {% else %}
              variable is not defined
          {% endif %}
  
      See the :func:`default` filter for a simple way to set undefined
      variables.
      """
      return not isinstance(value, Undefined)
  
imports: import operator
  import typing
  from collections import abc
  from numbers import Number
  from .runtime import Undefined
  from .utils import pass_environment
label_desc: Use image node_id 4 for calling a global function with example usage: test_defined(value) and returns: unknown